3. - According to skeletal evidence, the first group traveled to the Middle East
- After 80,000 frigid years , homosapiens crossed into Yemen through “Gates of Grief” (DNA Evidence).
- In 60,000 years H. Sapiens had traveled into Southeast Asia and Volcanic eruptions covered Asia, India
and Malaysia.
- Only about 70,000 years ago Modern men came across Australia.
- 50,000 years ago: Modern man began inhabiting Europe
- 1856 Neander, Germany – skeleton found – had different facial features, more adapted to climate.
WHERE HER MITOCHONDRIAL DNA
TRAVELED TO….
5. Also Called the Mitochondrial Eve
MITOCHONDRIAL EVE THEORY STATES
THAT THE MITOCHONDRIAL DNA IN ALL
HUMANS IS INHERITED FROM ONE
COMMON FEMALE ANCESTOR IN
AFRICA ~200,000 YEARS AGO. THIS IS
JUST ONE OF SEVERAL THEORIES
ABOUT HUMAN EVOLUTION THAT ARE
BEING DEBATED.
6. There are multiple explanations for how the Mitochondrial Eve theory, an example of it is
the bottleneck theory. The bottleneck theory is when a population undergoes a serve
evolutionary change, probably caused by a disease or natural disaster.
• The bottleneck effect could have occurred in that a large population of modern humans
may have greatly dwindled in size, therefore losing mitochondrial DNA. Some of the
remaining mating partners may not produce daughters where additional mitochondrial
DNA.
• Another possible way was a population of humans where a highly restricted speciation
event took place that caused some of the individuals to begin to evolve into modern
humans.
HOW IT OCCURRED
7. Cann et al
Cann et al. had examined the DNA of a group of people from five geographic populations.
He had discovered that
• All mtDNA genotypes could be traced back to a single, ancestral, mtDNA genotype.
• The woman responsible for the mtDNA, had lived in Africa about 200,000 years ago.
Cann et al. supported his findings with a parsimonious evolutionary tree that showed how
mtDNA derived from roots in Africa.
• He also found that the African population shows the most overall
mtDNA diversity.
THE DISCOVERY
8. During the 1980’s, several groups at UC Berkely used DNA restriction analysis to trace
maternal lineages of people sampled from around the world. Non-coding regions within
mitochondrial DNA accumulate neutral mutations rapidly and steadily. The number of
individuals sampled varied with each group, where 21, 147, and 241 individuals were
involved. They found many types of mitochondrial DNA that were separated into 2 groups, a
group of sub-Saharan Africans and a group consisting of N. Africans and all other population
groups. The fact that Africans are present in both groups suggest an African origin for
modern humans. They also showed that within the African population, there was much
more variation in mitochondrial DNA that any other group, indicating that the African
population has been established longer. The information generated from these studies was
used to calculate a mutation rate using geographical groups of known colonization or by
comparing the mutations among humans with the divergence of humans and chimpanzees.
It has been estimated that Mitochondrial Eve lived 150,000-200,000 years ago and that
mitochondrial DNA mutates 2-4% per million years.
MORE DISCOVERIES
